import pandas as pd
import numpy as np
dates=pd.date_range("20130101",periods=6)
df=pd.DataFrame(np.arange(24).reshape(6,4),index=dates,columns=["A","B","C","D"])
df.iloc[0,1]=np.nan
df.iloc[1,2]=np.nan
#print(df.dropna(axis=0,how="any"))#按行丢掉 how=any,all all的时候只有全部为nan才丢掉
print(df.fillna(value=0))
print(df.isnull())
print(np.any(df.isnull())==True)